This invention relates to a guide arrangement for minimizing the likelihood of an improper application of a pincer-like tightening tool for the plastic deformation of hose clamps provided with so-called xe2x80x9cOetikerxe2x80x9d ears.
Hose clamps with plastically deformable ears, so-called xe2x80x9cOetikerxe2x80x9d ears, which have been sold by the hundreds of millions, have enjoyed an immense commercial success. They are widely used, for example, on the assembly line of the automotive industry to tighten hoses onto nipples by the plastic deformation of the ear. Though infrequently, an improper positioning of the pincer-like tightening tools which on the assembly line are usually pneumatically operated, may cause an incorrect deformation of the ear. This, in turn, requires that the piece with the incorrectly deformed ear has to be taken out of the assembly line, the incorrectly installed clamp then has to be removed, and a new clamp has to be installed and tightened before the work piece can be re-entered on the assembly line. Because of time requirements and extra work, this is an annoyance which is to be avoided as far as possible.
The principal object of the present invention is to minimize the incorrect application of the tightening tool in hose clamps provided with plastically deformable ears. According to this invention, this is achieved by providing complementary guide profiles in the clamp and in the tightening tool so that the installer at the assembly line can interactively determine the correct application of the tightening tool when he or she senses mutual engagement of the guide profiles.
In one embodiment of the present invention involving so-called closed or endless clamps, guide surfaces are provided in the clamping ring by deep-drawn ridge-like embossments or projections forming male guide profiles extending outwardly within the areas of the connection of the clamping ring with the leg portions of the plastically deformable ear. The end surfaces of the jaws of the tightening tool are then provided with complementary notch-like cutouts forming female profiles so that the installer can feel the proper position of the tightening tool relative to the clamp when the notch-like cutouts are in engagement with the ridge-like embossments or projections.
In a preferred embodiment of this invention, which applies to so-called open clamps, usually made from galvanized steel or stainless steel band material, advantage is taken of the existence of overlapping band portions that exist from the point of the mechanical connection to the free end of the inner band portion when the mechanical connection, usually in the form of one or more hooks extending outwardly from the inner band portion into openings in the outer band portion, is engaged but before the plastically deformable ear in the outer band portion is plastically deformed to tighten the clamp. A typical clamp of this type is disclosed in U.S. Pat. No. 4,299,012 to Hans Oetiker. Once the mechanical connection is engaged, the inner band portion 11b will extend with its full width underneath the gap of the non-deformed ear. In a clamp of this type, the guide profiles are provided according to this invention in parts of the two mutually overlapping band portions as will be described more fully hereinafter. Again, correct application of the tightening tool can be interactively sensed by the installer when the mutually complementary guide profiles formed by deep-drawn outwardly extending embossments or projections in the inner band portion which, extending through narrow slots in the outer band portion, engage with the notch-like cut-outs in the jaw members of the tightening tool.